In September, the Sixth China Underwater Robot Professional Contest (2022-CURPC) was held. Guided by Professor Jiang Peng, the team of Wuhan University (WHU)from the GNSS Research Center (GNSSRC) won the competition’s subdivision in underwater acoustic communication decoding and identification intelligent algorithm.

Zhang Fengrui (left) and Han Zhen (right)

Organized by the National Natural Science Foundation of China (NNSF), the contest consisted of four rounds: preliminary (phase A), play-in (phase B), final (phase C), and oral defence phase. An embedded experiment was also required in phase C to test each team’s ability in receiving and processing information. The WHU team, achieving an information accuracy of 99.999%, 100%, and 100% in phases A, B, and C, respectively, ranked top during these first three phases, thereby eventually winning the championship of the underwater communication contest.

The embedded real-time underwater acoustic communication receiver made by the WHU team

While the result is indeed rewarding, the WHU team made huge efforts during the contest. Focused on the competition, the team aimed for the best in equipment implementation, striving to reproduce the underwater acoustic signal real-time receiving process on their own embedded platform. As they also needed to achieve real-time signal processing through an embedded platform with low computing power, the team readjusted their underwater acoustic channel equalization algorithm and developed a real-time frame synchronization detection method based on matched filter energy probability distribution, thereby succeeding in real-time synchronization of the signal frame.

In addition, facing poor channel data, the WHU team not only optimized the bidirectional equalizer structure and hybrid sparse self-adaptive update algorithm but also combined interpolation phase-locked loop to combat the Doppler effect, thus ensuring correct mediation of information. Furthermore, taking the sparseness of the channel into account, the team also compressed sensing technology for real-time processing at low computing power, seeking sparse solutions of equalizer soluble vectors.

Having performed remarkably well during the competition, when it gave its oral defence, the WHU team was unanimously approved by scholars from 18 universities and research institutes, including Peking University, Northwestern Polytechnical University, and the Chinese Academy of Science.

Over many years, the WHU team has dived into the field of underwater acoustic communication and positioning, cooperating naturally and efficiently. After winning the competition, the team members expressed their gratitude to Professor Jiang Peng. Once in charge of the development of Beidou’s first/second generation satellite receiver and a large depth Doppler acoustic log, Jiang proves to be careful and vigorous. While he endeavors to familiarize his students with basic theories, Jiang simultaneously emphasizes the vitalness of operational skills. Every week, he holds a seminar for students to elaborate on their daily research and exchange ideas.

According to Han Zhen, a member of the WHU team and doctoral student in GNSSRC, though Professor Jiang is busy with work, he always spares his time for the students, helping them with research difficulties and encouraging them to boldly undertake experiments. Also feeling grateful for Proessor Jiang’s patient guidance, Zhang Fengrui, a graduate student and also a member of the team, reflected, “Professor. Jiang is very experienced in engineering. He attends to our research processes every week and provides timely instructions every time he notices the gaps in our research.”

Prof. Jiang (left) and his students Han Zhen, Zhang Fengrui, and Zhang Yu

Since underwater acoustic communication is closely linked to China’s marine security, the team took marine security as the basis and the starting point of its research. Han Zhen told us, “While underwater acoustic communication seems fairly remote from us, it is actually closely related to our daily lives. The technology not only serves as the guard of China’s marine security but also applies to fields like underwater diving, marine ranching, and offshore platform monitoring.”

Students conducting fieldwork

For Jiang Peng, it is crucial that his students learn to apply their knowledge to practice by working on concrete projects. With him taking the lead, his team has achieved cross-medium information transmission between sea surface radio and underwater acoustics and is presently preparing for an underwater test of its underwater acoustic communication and range positioning integral system. As for the coming years, the team hopes to apply GPS theory and technology to places underwater in an attempt to improve the accuracy of underwater detection. Undertaking the cause assiduously and perseveringly, they also express their genuine wish that more talents could join them, thus jointly contributing to the development of China’s maritime power in the near future.

Rewritten by Sun Zhiwei

Edited by Li Jing, Xi Bingqing, Sylvia